Abstract
According to the technical literature and experience, pipe-steels of the same grade working in almost the same environment containing H2S have a different sensitivity to hydrogen induced cracking (HIC). Reaction of the wet hydrogen sulfide with iron produces the hydrogen atoms which can be easily absorbed by the iron matrix due to their small diameter and high coefficient of diffusivity at ambient temperatures. In some places as for instance interphase boundaries (Steel matrix-nonmetallic inclusions), the hydrogen atoms are recombining into molecules creating pressure in these sites.....